Direct aqueous phase reforming of bio-based feedstocks

ABSTRACT

A method comprises providing a bio-based feedstock; contacting the bio-based feedstock with a solvent in a hydrolysis reaction to form an intermediate stream comprising carbohydrates; contacting the intermediate stream with an apr catalyst to form a plurality of oxygenated intermediates, wherein a first portion of the oxygenated intermediates are recycled to form the solvent; and processing at least a second portion of the oxygenated intermediates to form a fuel blend.

The present application claims the benefit of pending U.S. ProvisionalPatent Application Ser. No. 61/291,572, filed Dec. 31, 2009 the entiredisclosure of which is hereby incorporated by reference.

FIELD OF THE INVENTION

A significant amount of attention has been placed on developing newtechnologies for providing energy from resources other than fossilfuels. Biomass is a resource that shows promise as a fossil fuelalternative. As opposed to fossil fuel, biomass is also renewable.

BACKGROUND OF THE INVENTION

Biomass may be useful as a source of renewable fuels. One type ofbiomass is plant biomass. Plant biomass is the most abundant source ofcarbohydrate in the world due to the lignocellulosic materials composingthe cell walls in higher plants. Plant cell walls are divided into twosections, primary cell walls and secondary cell walls. The primary cellwall provides structure for expanding cells and is composed of threemajor polysaccharides (cellulose, pectin, and hemicellulose) and onegroup of glycoproteins. The secondary cell wall, which is produced afterthe cell has finished growing, also contains polysaccharides and isstrengthened through polymeric lignin covalently cross-linked tohemicellulose. Hemicellulose and pectin are typically found inabundance, but cellulose is the predominant polysaccharide and the mostabundant source of carbohydrates.

Most transportation vehicles require high power density provided byinternal combustion and/or propulsion engines. These engines requireclean burning fuels which are generally in liquid form or, to a lesserextent, compressed gases. Liquid fuels are more portable due to theirhigh energy density and their ability to be pumped, which makes handlingeasier.

Currently, bio-based feedstocks such as biomass provides the onlyrenewable alternative for liquid transportation fuel. Unfortunately, theprogress in developing new technologies for producing liquid biofuelshas been slow in developing, especially for liquid fuel products thatfit within the current infrastructure. Although a variety of fuels canbe produced from biomass resources, such as ethanol, methanol,biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogenand methane, these fuels require either new distribution technologiesand/or combustion technologies appropriate for their characteristics.The production of these fuels also tends to be expensive and raisequestions with respect to their net carbon savings.

Carbohydrates are the most abundant, naturally occurring biomolecules.Plant materials store carbohydrates either as sugars, starches,celluloses, lignocelluloses, hemicelluloses, and any combinationthereof. In one embodiment, the carbohydrates include monosaccharides,polysaccharides or mixtures of monosaccharides and polysaccharides. Asused herein, the term “monosaccharides” refers to hydroxy aldehydes orhydroxy ketones that cannot be hydrolyzed to smaller units. Examples ofmonosaccharides include, but are not limited to, dextrose, glucose,fructose and galactose. As used herein, the term “polysaccharides”refers to saccharides comprising two or more monosaccharide units.Examples of polysaccharides include, but are not limited to, cellulose,sucrose, maltose, cellobiose, and lactose. Carbohydrates are producedduring photosynthesis, a process in which carbon dioxide is convertedinto organic compounds as a way to store energy. The carbohydrates arehighly reactive compounds that can be easily oxidized to generateenergy, carbon dioxide, and water. The presence of oxygen in themolecular structure of carbohydrates contributes to the reactivity ofthe compound. Water soluble carbohydrates react with hydrogen overcatalyst(s) to generate polyols and sugar alcohols, either byhydrogenation, hydrogenolysis or both.

U.S. Publication No. 20080216391 to Cortright et al. describes a processfor converting carbohydrates to higher hydrocarbons by passingcarbohydrates through a hydrogenation reaction followed by an AqueousPhase Reforming (“APR”) process. The hydrogenation reaction producespolyhydric alcohols that can withstand the conditions present in the APRreaction. Further processing in an APR reaction and a condensationreaction can produce a higher hydrocarbon for use as a fuel. CurrentlyAPR is limited to feedstocks including sugars or starches, whichcompetes with the use of these materials for food resulting in a limitedsupply. There is a need to directly process bio-based feedstocksincluding “biomass”, or lignocellulosic feedstocks, into liquid fuels.

SUMMARY OF THE INVENTION

An embodiment of the present invention comprises providing a bio-basedfeedstock; contacting the bio-based feedstock with a solvent in ahydrolysis reaction to form an intermediate stream comprisingcarbohydrates; contacting the intermediate stream with an APR catalystto form a plurality of oxygenated intermediates, wherein a first portionof the oxygenated intermediates are recycled to form the solvent; andprocessing at least a second portion of the oxygenated intermediates toform a fuel blend.

Another embodiment of the present invention comprises a methodcomprising providing a bio-based feedstock; contacting the bio-basedfeedstock with a hydrolysis catalyst and a solvent to form anintermediate stream comprising carbohydrates; contacting at least aportion of the intermediate stream with a hydrogenolysis catalyst in thepresence of first hydrogen source to form at least some hydrogenolysisreaction products; contacting at least a portion of the intermediatestream with a hydrogenation catalyst in the presence of second hydrogensource to form at least some hydrogenation reaction products; contactingat least a portion of the intermediate stream with an APR catalyst toform an APR reaction product; wherein at least a portion of thehydrogenolysis reaction products, at least a portion of thehydrogenation reaction products, and at a least a portion of the APRreaction products are combined to form a plurality of oxygenatedintermediates, wherein a first portion of the oxygenated intermediatesare recycled to form the solvent; and processing at least a secondportion of the oxygenated intermediates to form a fuel blend.

Still another embodiment of the present invention comprises a systemcomprising a hydrolysis reactor operating under hydrolysis conditionsfor receiving a bio-based feedstock and a solvent and discharging anintermediate stream comprising a carbohydrate; an APR reactor comprisingan APR catalyst for receiving the intermediate stream and discharging anoxygenated intermediate stream, wherein a first portion of theoxygenated intermediate stream is recycled to the hydrolysis reactor asthe solvent; and a fuels processing reactor for receiving a secondportion of the oxygenated intermediate stream and discharging a fuelblend.

The features and advantages of the invention will be apparent to thoseskilled in the art. While numerous changes may be made by those skilledin the art, such changes are within the spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments ofthe invention, and should not be used to limit or define the invention.

FIG. 1 schematically illustrates a block flow diagram of an embodimentof a higher hydrocarbon production process of this invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to the production of higher hydrocarbons suitablefor use in transportation fuels and industrial chemicals from bio-basedfeedstocks, such as biomass, carbohydrates, which include sugars, sugaralcohols, celluloses, lignocelluloses, hemicelluloses, and anycombination thereof. The higher hydrocarbons produced are useful informing transportation fuels, such as synthetic gasoline, diesel fuel,and jet fuel, as well as industrial chemicals. As used herein, the term“higher hydrocarbons” refers to hydrocarbons having an oxygen to carbonratio less than the oxygen to carbon ratio of at least one component ofthe bio-based feedstock. As used herein the term “hydrocarbon” refers toan organic compound comprising primarily hydrogen and carbon atoms,which is also an unsubstituted hydrocarbon. In certain embodiments, thehydrocarbons of the invention also comprise heteroatoms (i.e., oxygen orsulfur) and thus the term “hydrocarbon” may also include substitutedhydrocarbons.

The methods and systems of the invention have an advantage of convertinga raw bio-based feedstock through hydrolysis and APR reactions to forman oxygenated intermediate stream comprising polyols, alcohols, ketones,aldehydes, and other mono-oxygenated reaction products that can be feddirectly to a condensation reactor to form higher hydrocarbons, whichresults in an increased conversion and conversion efficiency andminimizes the formation of unwanted by-products such as carmelins. Whilenot intending to be limited by theory, it is believed that bycontrolling the concentration of carbohydrates fed to an APR process,degradation of carbohydrate at APR conditions can be minimized. Anotheradvantage is that the invention provides methods that reduce the amountof unwanted byproducts, thereby improving the overall yield of productsrelative to the carbohydrates extracted from the bio-based feedstock.The invention reduces both the degradation products formed uponextraction of carbohydrates from the biomass and, through subsequentprocessing in an APR reaction, the amount of coke formed in theprocessing reactions to form a fuel blend. In some embodiments,oxygenated intermediates produced in the APR reaction are recycledwithin the process and system to form the in situ generated solvent,which is used in the bio-based feedstock digestion process. This recyclesaves costs and can increase the amount of carbohydrates extracted fromthe bio-based feedstock. Further, by controlling the degradation ofcarbohydrate in the APR process, the hydrogenation reaction can beconducted along with the APR reaction at temperatures ranging from 175°C. to 275° C. As a result, a separate hydrogenation reaction can beavoided and the fuel forming potential of the bio-based feedstock fed tothe process can be increased. This process and reaction scheme describedherein also results in a capital cost savings and process operationalcost savings. Advantages of specific embodiments will be described inmore detail below.

In some embodiments, the invention provides methods comprising:providing a bio-based feedstock; contacting the bio-based feedstock witha solvent in a hydrolysis reaction to form an intermediate streamcomprising carbohydrates; contacting the intermediate stream with an APRcatalyst to form a plurality of oxygenated intermediates, wherein afirst portion of the oxygenated intermediates are recycled to form thesolvent; and processing at least a second portion of the oxygenatedintermediates to form a fuel blend.

FIG. 1 shows an embodiment of a method of the present invention in whichhydrolysis of a bio-based feedstock occurs in hydrolysis reaction 114 toproduce an intermediate stream comprising carbohydrates 116, theintermediate stream 116 is fed to an APR reaction 122, and then outletstream 124 (and optionally 128) are fed to a condensation reaction 130to produce higher hydrocarbons.

In some embodiments, the reactions described below are carried out inany system of suitable design, including systems comprisingcontinuous-flow, batch, semi-batch or multi-system vessels and reactors.One or more reactions may take place in an individual vessel and theprocess is not limited to separate reaction vessels for each reaction.In some embodiments the system of the invention utilizes a fluidizedcatalytic bed system. Preferably, the invention is practiced using acontinuous-flow system at steady-state equilibrium.

As used herein, the term “bio-based feedstock” means organic materialsproduced by plants (e.g., leaves, roots, seeds and stalks), andmicrobial and animal metabolic wastes. Bio-based feedstocks can includebiomass. Common sources of biomass include: agricultural wastes (e.g.,corn stalks, straw, seed hulls, sugarcane leavings, bagasse, nutshells,and manure from cattle, poultry, and hogs); wood materials (e.g., woodor bark, sawdust, timber slash, and mill scrap); municipal waste (e.g.,waste paper and yard clippings); and energy crops (e.g., poplars,willows, switch grass, alfalfa, prairie bluestream, corn, soybean). Theterm “biomass” also refers to the primary building blocks of all theabove, including, but not limited to, saccharides, lignins, celluloses,hemicelluloses, and starches. Bio-based feedstocks can be a source ofcarbohydrates.

FIG. 1 shows an embodiment of the present invention for convertingbio-based feedstocks into fuel products. In this embodiment, a bio-basedfeedstock 112 is introduced to a hydrolysis reaction 114 along with arecycle stream 118. The recycle stream 118 can comprise a number ofcomponents including in situ generated solvents, which may be useful insolvating sugars and lignins from the bio-based feedstock during thehydrolysis reaction. The term “in situ” as used herein refers to acomponent that is produced within the overall process; it is not limitedto a particular reactor for production or use and is thereforesynonymous with an in process generated component. The in situ generatedsolvents may comprise oxygenated intermediates. The hydrolysis reactionmay comprise a hydrolysis catalyst (e.g., a metal or acid catalyst) toaid in the hydrolysis reaction. The reaction conditions in thehydrolysis reaction may vary within the reaction media so that atemperature gradient exists within the reaction media, allowing forhemi-cellulose to be extracted at a lower temperature than cellulose.For example, the reaction media may comprise an increasing temperaturegradient from the bio-based feedstock 112. The non-extractable solidsmay be removed from the reaction as an outlet stream 120. Theintermediate carbohydrate stream 116 is an intermediate stream that maycomprise the hydrolyzed biomass in the form of carbohydrates. Thecomposition of the intermediate carbohydrate stream 116 may vary and maycomprise a number of different compounds. Preferably, the carbohydrateshave 2 to 12 carbon atoms, and even more preferably 2 to 6 carbon atoms.The carbohydrates may also have an oxygen to carbon ratio from 0.5:1 to1:1.2.

Various factors affect the conversion of the bio-based feedstock in thehydrolysis reaction. In some embodiments, hemi-cellulose can beextracted from the bio-based feedstock within an aqueous fluid andhydrolyzed at temperatures below 160° C. to produce a C₅ carbohydratefraction. At increasing temperatures, this C₅ fraction can be thermallydegraded. It is therefore advantageous to convert the C₅, C₆, or othersugar intermediates directly into more stable intermediates such assugar alcohols. Even these intermediates can further degrade, such thatrunning the APR reaction to convert them to polyols such as glycerol,ethylene glycol, propylene glycol, and mono-oxygenates is preferred toincrease process yields. By recycling the oxygenated intermediates fromthe APR reaction and performing additional biomass hydrolysis with thisrecycled liquid, the concentration of active oxygenated intermediatescan be increased to commercially viable concentrations without waterdilution. Typically, a concentration of at least 2%, or 5% or preferablegreater than 8% of organic intermediates in water, may be suitable for aviable process. This may be determined by sampling the intermediatestream at the outlet of the hydrolysis reaction and using a suitabletechnique such as chromatography to identify the concentration of totalorganics. The oxygenated intermediate stream has a fuel formingpotential, as described below.

Cellulose extraction begins above 160° C., with solubilization andhydrolysis becoming complete at temperatures around 190° C., aided byorganic acids (e.g., carboxylic acids) formed from partial degradationof carbohydrate components. Some lignins can be solubilized beforecellulose, while other lignins may persist to higher temperatures.Organic in situ generated solvents, which may comprise a portion of theoxygenated intermediates, including, but not limited to, light alcoholsand polyols, can assist in solubilization and extraction of lignin andother components.

At temperatures ranging from about 125° C. to 275° C., carbohydrates candegrade through a series of complex self-condensation reactions to formcaramelans, which are considered degradation products that are difficultto convert to fuel products. In general, some degradation reactions canbe expected with aqueous reaction conditions upon application oftemperature, given that water will not completely suppressoligomerization and polymerization reactions.

In some embodiments of the invention, the bio-based feedstock ishydrolyzed in a liquid medium such an aqueous solution to obtain anintermediate carbohydrates stream for use in the process. There arevarious suitable bio-based feedstock hydrolysis reaction methods,including, but not limited to, acid hydrolysis, alkaline hydrolysis,enzymatic hydrolysis, catalytic hydrolysis, and hydrolysis usinghot-compressed water. In certain embodiments, the hydrolysis reactioncan occur at a temperature between 100° C. and 250° C. and pressurebetween 1 atm and 100 atm. In embodiments including strong acid andenzymatic hydrolysis, the hydrolysis reaction can occur at temperaturesas low as ambient temperature and pressure between 1 atm and 100 atm. Insome embodiments, the hydrolysis reaction may comprise a hydrolysiscatalyst (e.g., a metal or acid catalyst) to aid in the hydrolysisreaction. The catalyst can be any catalyst capable of effecting ahydrolysis reaction. For example, suitable catalysts can include, butare not limited to, acid catalysts, base catalysts, metal catalysts, andany combination thereof. Acid catalysts can include organic acids suchas acetic, formic, levulinic acid, and any combination thereof. In anembodiment the acid catalyst may be generated in the APR reaction andcomprise a component of the oxygenated intermediate stream.

In some embodiments, the aqueous solution may contain an in situgenerated solvent. The in situ generated solvent generally comprises atleast one alcohol or polyol capable of solvating one or more hydrolysisreaction products or other components of the bio-based feedstock. Forexample, an alcohol may be useful for solvating lignin from a biomassfeedstock for use within the process. The in situ generated solvent mayalso include one or more organic acids. In some embodiments, the organicacid can act as a catalyst in the hydrolysis of the bio-based feedstock.Each in situ generated solvent component may be supplied by an externalsource or it may be generated within the process and recycled to thehydrolysis reactor. For example, a portion of the oxygenatedintermediates produced in the APR reaction may be separated in theseparator stage for use as the in situ generated solvent in thehydrolysis reaction. In an embodiment, the in situ generated solvent canbe separated, stored, and selectively injected into the recycle streamso as to maintain a desired concentration in the recycle stream.

The temperature of the hydrolysis reaction can be chosen so that themaximum amount of extractable carbohydrates are hydrolyzed and extractedas carbohydrates from the bio-based feedstock while limiting theformation of degradation products. In some embodiments, a plurality ofreactor vessels may be used to carry out the hydrolysis reaction. Thesevessels may have any design capable of carrying out a hydrolysisreaction. Suitable reactor vessel designs can include, but are notlimited to, co-current, counter-current, stirred tank, or fluidized bedreactors. In this embodiment, the bio-based feedstock may first beintroduced into a reactor vessel operating at approximately 160° C. Atthis temperature the hemicellulose may be hydrolyzed to extract the C₅carbohydrates and some lignin without degrading these products. Theremaining bio-based feedstock solids may then exit the first reactorvessel and pass to a second reactor vessel. The second vessel may beoperated between 160° C. and 250° C. so that the cellulose is furtherhydrolyzed to form C₆ carbohydrates. The remaining bio-based feedstocksolids may then exit the second reactor as a waste stream while theintermediate stream from the second reactor can be cooled and combinedwith the intermediate stream from the first reactor vessel. The combinedoutlet stream may then pass to the APR reactor. In another embodiment, aseries of reactor vessels may be used with an increasing temperatureprofile so that a desired carbohydrate fraction is extracted in eachvessel. The outlet of each vessel can then be cooled prior to combiningthe streams, or the streams can be individually fed to the APR reactionfor conversion of the intermediate carbohydrate streams to one or moreoxygenated intermediate streams.

In another embodiment, the hydrolysis reaction as shown in FIG. 1 maytake place in a single vessel. This vessel may have any design capableof carrying out a hydrolysis reaction. Suitable reactor vessel designscan include, but are not limited to, co-current, counter-current,stirred tank, or fluidized bed reactors. In some embodiments, acounter-current reactor design is used in which the biomass flowscounter-current to the aqueous stream, which may comprise an in situgenerated solvent. In this embodiment, a temperature profile may existwithin the reactor vessel so that the temperature within the hydrolysisreaction media at or near the bio-based feedstock inlet is approximately160° C. and the temperature near the bio-based feedstock outlet isapproximately 200° C. to 250° C. The temperature profile may be obtainedthrough the introduction of an aqueous fluid comprising an in situgenerated solvent above 200° C. to 250° C. near the bio-based feedstockoutlet while simultaneously introducing a bio-based feedstock at 160° C.or below. The specific inlet temperature of the aqueous fluid and thebio-based feedstock will be determined based a heat balance between thetwo streams. The resulting temperature profile may be useful for thehydrolysis and extraction of cellulose, lignin, and hemicellulosewithout the substantial production of degradation products.

Other means may be used to establish an appropriate temperature profilefor the hydrolysis reaction and extraction of cellulose andhemicellulose along with other components such as lignin withoutsubstantially producing degradation products. For example, internal heatexchange structures may be used within one or more reaction vessels tomaintain a desired temperature profile for the hydrolysis reaction.Other structures as would be known to one of ordinary skill in the artmay also be used.

Each reactor vessel of the invention preferably includes an inlet and anoutlet adapted to remove the product stream from the vessel or reactor.In some embodiments, the vessel in which hydrolysis reaction or someportion of the hydrolysis reaction occurs may include additional outletsto allow for the removal of portions of the reactant stream to helpmaximize the desired product formation. Suitable reactor designs caninclude, but are not limited to, a backmixed reactor (e.g., a stirredtank, a bubble column, and/or a jet mixed reactor) may be employed ifthe viscosity and characteristics of the partially digested bio-basedfeedstock and liquid reaction media is sufficient to operate in a regimewhere bio-based feedstock solids are suspended in an excess liquid phase(as opposed to a stacked pile digester).

The relative composition of the various carbohydrate components in theintermediate carbohydrate stream in the methods of the present inventionaffects the formation of undesirable by-products such as coke in the APRreaction. In particular, a low concentration of carbohydrates in theintermediate stream can affect the formation of unwanted by-products. Inpreferred embodiments, it is desirable to have a concentration of nomore than 5% of readily degradable carbohydrates or heavy end precursorsin the intermediate stream, while maintaining a total organicintermediates concentration, which includes the oxygenated intermediates(e.g., mono-oxygenates and/or diols), concentration as high as possiblevia use of the recycle concept.

In some embodiments of the invention, the carbohydrates in theintermediate carbohydrate stream produced by the hydrolysis reaction arepartially de-oxygenated by adding hydrogen or another suitable catalystto the hydrolysis reactor.

APR converts polyhydric alcohols to aldehydes, which react over acatalyst with water to form hydrogen, carbon dioxide, and oxygenatedintermediates, which comprise smaller polyhydric alcohols. Thepolyhydric alcohols can further react through a series of deoxygenationreactions to form additional oxygenated intermediates that can producehigher hydrocarbons through a condensation reaction.

Referring again to FIG. 1, according to one embodiment, the intermediatecarbohydrate stream 116 from the hydrolysis reaction 114 can be passedto an APR reaction to produce oxygenated intermediates. Intermediatecarbohydrate stream 116 can comprise C₅ and C₆ carbohydrates that can bereacted in the APR reaction. For embodiments comprising thermocatalyticAPR, oxygenated intermediates such as sugar alcohols, sugar polyols,carboxylic acids, and furans can be converted to fuels. The APR reactioncan comprise an APR catalyst to aid in the reactions taking place. TheAPR reaction conditions can be such that an APR reaction can take placealong with a hydrogenation reaction, a hydrogenolysis reaction, or bothas many of the reaction conditions overlap or are complimentary. Thevarious reactions can result in the formation of one or more oxygenatedintermediate streams 124. As used herein, an “oxygenated intermediate”can include one or more polyols, alcohols, ketones, or any otherhydrocarbon having at least one oxygen atom.

In some embodiments, the APR catalysts can be a heterogeneous catalystcapable of catalyzing a reaction between hydrogen and carbohydrate,oxygenated intermediate, or both to remove one or more oxygen atoms toproduce alcohols and polyols to be fed to the condensation reactor. TheAPR catalyst can generally include Cu, Re, Ni, Fe, Co, Ru, Pd, Rh, Pt,Os, Ir, and alloys or any combination thereof, either alone or withpromoters such as W, Mo, Au, Ag, Cr, Zn, Mn, Sn, B, P, Bi, and alloys orany combination thereof. Other effective APR catalyst materials includeeither supported nickel or ruthenium modified with rhenium. In someembodiments, the APR catalyst also includes any one of the supports,depending on the desired functionality of the catalyst. The APRcatalysts may be prepared by methods known to those of ordinary skill inthe art. In some embodiments the APR catalyst includes a supported GroupVIII metal catalyst and a metal sponge material (e.g., a sponge nickelcatalyst). Raney nickel provides an example of an activated spongenickel catalyst suitable for use in this invention. In some embodiments,the APR reaction in the invention is performed using a catalystcomprising a nickel-rhenium catalyst or a tungsten-modified nickelcatalyst. One example of a suitable catalyst for the APR reaction of theinvention is a carbon-supported nickel-rhenium catalyst.

In some embodiments, a suitable Raney nickel catalyst may be prepared bytreating an alloy of approximately equal amounts by weight of nickel andaluminum with an aqueous alkali solution, e.g., containing about 25weight % of sodium hydroxide. The aluminum is selectively dissolved bythe aqueous alkali solution resulting in a sponge shaped materialcomprising mostly nickel with minor amounts of aluminum. The initialalloy includes promoter metals (i.e., molybdenum or chromium) in theamount such that 1 to 2 weight % remains in the formed sponge nickelcatalyst. In another embodiment, the APR catalyst is prepared using asolution of ruthenium(III) nitrosylnitrate, ruthenium (III) chloride inwater to impregnate a suitable support material. The solution is thendried to form a solid having a water content of less than 1% by weight.The solid is then reduced at atmospheric pressure in a hydrogen streamat 300° C. (uncalcined) or 400° C. (calcined) in a rotary ball furnacefor 4 hours. After cooling and rendering the catalyst inert withnitrogen, 5% by volume of oxygen in nitrogen is passed over the catalystfor 2 hours.

In certain embodiments, the APR catalyst may include a catalyst support.The catalyst support stabilizes and supports the catalyst. The type ofcatalyst support used depends on the chosen catalyst and the reactionconditions. Suitable supports for the invention include, but are notlimited to, carbon, silica, silica-alumina, zirconia, titania, ceria,vanadia, nitride, boron nitride, heteropolyacids, hydroxyapatite, zincoxide, chromia, zeolites, carbon nanotubes, carbon fullerene and anycombination thereof.

The conditions for which to carry out the APR reaction will vary basedon the type of starting material and the desired products. In general,the APR reaction is conducted at temperatures of 80° C. to 300° C., andpreferably at 120° C. to 300° C., and most preferably at 200° C. to 280°C. In some embodiments, the APR reaction is conducted at pressures from500 KPa to 14000 KPa.

The APR product stream 124 may comprise APR products that includeoxygenated intermediates. As used herein, “oxygenated intermediates”generically refers to hydrocarbon compounds having 1 or more carbonatoms and between 1 and 3 oxygen atoms (referred to herein as C₁+O₁₋₃hydrocarbons), such as alcohols, ketones, aldehydes, furans, hydroxycarboxylic acids, carboxylic acids, diols and triols. Preferably, theoxygenated intermediates have from 1 to 6 carbon atoms, or 2 to 6 carbonatoms, or 3 to 6 carbon atoms. Alcohols may include, without limitation,primary, secondary, linear, branched or cyclic C₁+ alcohols, such asmethanol, ethanol, n-propyl alcohol, isopropyl alcohol, butyl alcohol,isobutyl alcohol, butanol, pentanol, cyclopentanol, hexanol,cyclohexanol, 2-methyl-cyclopentanonol, heptanol, octanol, nonanol,decanol, undecanol, dodecanol, and isomers thereof. The ketones mayinclude, without limitation, hydroxyketones, cyclic ketones, diketones,acetone, propanone, 2-oxopropanal, butanone, butane-2,3-dione,3-hydroxybutane-2-one, pentanone, cyclopentanone, pentane-2,3-dione,pentane-2,4-dione, hexanone, cyclohexanone, 2-methyl-cyclopentanone,heptanone, octanone, nonanone, decanone, undecanone, dodecanone,methylglyoxal, butanedione, pentanedione, diketohexane, and isomersthereof. The aldehydes may include, without limitation,hydroxyaldehydes, acetaldehyde, propionaldehyde, butyraldehyde,pentanal, hexanal, heptanal, octanal, nonal, decanal, undecanal,dodecanal, and isomers thereof. The carboxylic acids may include,without limitation, formic acid, acetic acid, propionic acid, butanoicacid, pentanoic acid, hexanoic acid, heptanoic acid, isomers andderivatives thereof, including hydroxylated derivatives, such as2-hydroxybutanoic acid and lactic acid. The diols may include, withoutlimitation, ethylene glycol, propylene glycol, 1,3-propanediol,butanediol, pentanediol, hexanediol, heptanediol, octanediol,nonanediol, decanediol, undecanediol, dodecanediol, and isomers thereof.The triols may include, without limitation, glycerol, 1,1,1tris(hydroxymethyl)-ethane (trimethylolethane), trimethylolpropane,hexanetriol, and isomers thereof. Furans and furfurals include, withoutlimitation, furan, tetrahydrofuran, dihydrofuran, 2-furan methanol,2-methyl-tetrahydrofuran, 2,5-dimethyl-tetrahydrofuran, 2-methyl furan,2-ethyl-tetrahydrofuran, 2-ethyl furan, hydroxylmethylfurfural,3-hydroxytetrahydrofuran, tetrahydro-3-furanol, 2,5-dimethyl furan,5-hydroxymethyl-2(5H)-furanone,dihydro-5-(hydroxymethyl)-2(3H)-furanone, tetrahydro-2-furoic acid,dihydro-5-(hydroxymethyl)-2(3H)-furanone, tetrahydrofurfuryl alcohol,1-(2-furyl)ethanol, hydroxymethyltetrahydrofurfural, and isomersthereof.

The oxygenated intermediate stream may generally be characterized ascomprising components corresponding to the formula: C_(n)O_(m), whereinn=1-6 and m=1 to 6, and m≦n. Other elements such as hydrogen may also bepresent in these molecules. Additional components that may be present inthe APR products stream can include hydrogen and other gases such ascarbon dioxide. These components can be separated from the oxygenatedintermediates or they can be fed to the condensation reaction forremoval after the condensation reaction.

In a preferred embodiment, hydrogenation and hydrogenolysis take placein the APR reactor because the same catalysts and conditions areapplicable to all three reactions. Hydrogenation and hydrogenolysisreactions are discussed in more detail below. These reactions may beoptionally employed in the methods of the invention either separate fromAPR or in conjunction with APR. One of ordinary skill in the art, withthe benefit of this disclosure, would know what conditions to choose tomaximize the desired product of the hydrogenation, hydrogenolysis, andAPR reactions. The inclusion of all three reactions in a single reactionstep may have an advantage of process intensification and cost reductionrelative to a process in which the three reactions are carried out inseparate vessels. Additional process equipment may be present to movethe products streams between reactors in specific embodiments. Forexample, pumps may be used to pass a fluid product stream betweenreactor vessels when multiple vessels are used.

In some embodiments of the invention, optionally, it is desirable toconvert the carbohydrates and oxygenated intermediates from thehydrolysis reaction and APR reaction to smaller molecules. A suitablemethod for this conversion is through a hydrogenolysis reaction.

Various processes are known for performing hydrogenolysis. One suitablemethod includes contacting a carbohydrate or oxygenated intermediatewith hydrogen or hydrogen mixed with a suitable gas and a hydrogenolysiscatalyst in a hydrogenolysis reaction under conditions sufficient toform a reaction product comprising smaller molecules or polyols. As usedherein, the term “smaller molecules or polyols” includes any moleculethat has a smaller molecular weight, which can include a smaller numberof carbon atoms or oxygen atoms, than the starting carbohydrate. In someembodiments, the reaction products include smaller molecules thatinclude polyols and alcohols. Someone of ordinary skill in the art wouldbe able to choose the appropriate method by which to carry out thehydrogenolysis reaction.

In some embodiments, a 5 and/or 6 carbon carbohydrate molecule can beconverted to propylene glycol, ethylene glycol, and glycerol using ahydrogenolysis reaction in the presence of a hydrogenolysis catalyst.The hydrogenolysis catalyst may include the same catalysts discussedabove relative to the APR catalyst. In certain embodiments, the catalystdescribed in the hydrogenolysis reaction can include a catalyst supportas described above for the APR catalyst.

The conditions for which to carry out the hydrogenolysis reaction willvary based on the type of starting material and the desired products.One of ordinary skill in the art, with the benefit of this disclosure,will recognize the appropriate conditions to use to carry out thereaction. In general, the hydrogenolysis reaction may be conducted attemperatures of 110° C. to 300° C., and preferably at 170° C. to 220°C., and most preferably at 200° C. to 225° C. In some embodiments, thehydrogenolysis reaction is conducted under basic conditions, preferablyat a pH of 8 to 13, and even more preferably at a pH of 10 to 12. Insome embodiments, the hydrogenolysis reaction is conducted at pressuresin a range between 60 KPa and 16500 KPa, and preferably in a rangebetween 1700 KPa and 14000

KPa, and even more preferably between 4800 KPa and 11000 KPa. In certainembodiments, the conditions described in the hydrogenolysis reactionwill be the same as described above for the APR and hydrogenationreaction since the reaction can occur in the same reactor.

The carbohydrates, oxygenated intermediates, or both may take place in ahydrogenation reaction to saturate one or more unsaturated bonds.Various processes are suitable for hydrogenating carbohydrates,oxygenated intermediates, or both. One method includes contacting thefeed stream with hydrogen or hydrogen mixed with a suitable gas and acatalyst under conditions sufficient to cause a hydrogenation reactionto form a hydrogenated product. In some embodiments, suitablehydrogenation catalysts may be selected from the list of APR catalystsprovided above.

The conditions for which to carry out the hydrogenation reaction willvary based on the type of starting material and the desired products.One of ordinary skill in the art, with the benefit of this disclosure,will recognize the appropriate reaction conditions. In general, thehydrogenation reaction is conducted at temperatures of 80° C. to 250°C., and preferably at 90° C. to 200° C., and most preferably at 100° C.to 150° C. In some embodiments, the hydrogenolysis reaction is conductedat pressures from 500 KPa to 14000 KPa. In some embodiments, theconditions of this reaction match those for the APR reaction

The hydrogen used in the hydrogenation reaction of the current inventioncan include external hydrogen, recycled hydrogen, in situ generatedhydrogen, and any combination thereof. As used herein, the term“external hydrogen” refers to hydrogen that does not originate from abio-based feedstock reaction itself, but rather is added to the systemfrom another source.

In some embodiments, the APR, the hydrogenation and hydrogenolysiscatalysts are the same and may exist in the same bed in the same reactorvessel. Each reactor vessel of the invention preferably includes aninlet and an outlet adapted to remove the product stream from the vesselor reactor. In some embodiments, the vessels and reactors includeadditional outlets to allow for the removal of portions of the reactantstream to help maximize the desired product formation, and allow forcollection and recycling of byproducts for use in other portions of thesystem.

In some embodiments, in the APR reaction, oxygenated intermediates maybe produced by catalytically reacting a carbohydrates in the presence ofan APR catalyst at a reforming temperature and reforming pressure toproduce hydrogen, and catalytically reacting the produced hydrogen witha portion of the carbohydrates over a hydrogenation/hydrogenolysiscatalyst and deoxygenation pressure and temperature to produce thedesired oxygenated intermediates. In certain embodiments, the hydrogenused can entirely be provided by an external source or supplemented byan external source. In another embodiment, the oxygenate intermediatesmay also include recycled oxygenated intermediates.

Without intending to be limited by theory, the reactions comprisingbio-based feedstock conversion via APR can be expressed as:

Biomass (B) hydrolysis→sugar: r _(s) =k _(OH) B  (Eq. 1)

Sugar degradation→heavy ends: r _(s) =−k _(d) S ²  (Eq. 2)

Sugar (S) hydrogenation→to sugar alcohol (A): r _(s) =−k _(H) w _(H) P_(H2) S  (Eq. 3)

Sugar alcohol (A) APR→desired products: r _(A) =−k _(R) w _(R) A  (Eq.4)

Oxygenated intermediates, which comprise sugar alcohols, are thought tobe more stable under APR reaction conditions than carbohydrates such assugars, such that higher concentrations of oxygenated intermediates canbe tolerated in the reaction mixture without an excessive formation ofdegradation products. Despite somewhat improved stability for oxygenatedintermediates, the residence time of liquid phases at APR temperaturesrelative to APR catalytic contact time can be minimized in order todecrease yield losses to degradation products. One consideration in theprocess design is to react the carbohydrates to the desired oxygenatedintermediates (Eq. 3), and continue on to the desired reaction products(Eq. 4) as soon as they are formed by hydrolysis (Eq. 1) and before thecarbohydrate degradation reaction of Eq. 2 can occur. Anotherconsideration includes the reaction conditions of the carbohydratesinvolved. The C₅ carbohydrates from hemicellulose are extracted attemperatures around 160° C., whereas the C₆ carbohydrates are extractedfollowing cellulose hydrolysis at temperatures above 160° C., whichcould result in the rapid degradation of the C₅ carbohydrates. Addingreactions involving formation or consumption of carbohydrate S andsolving for the steady state concentration gives:

$\begin{matrix}{S = \frac{{k_{OH}B} - {k_{d}S^{2}}}{k_{H}w_{H}P_{H\; 2}}} & \left( {{Eq}.\mspace{14mu} 5} \right)\end{matrix}$

while degradation products relative to yield of desired intermediates isgiven by:

$\begin{matrix}{\frac{- r_{d}}{r_{H}} = \frac{k_{d}S}{k_{H}w_{H}P_{H\; 2}}} & \left( {{Eq}.\mspace{14mu} 6} \right)\end{matrix}$

While only theoretical, Eq. 6 tends to indicate that to reduce yieldloss to degradation products, the carbohydrate concentration (i.e., S)should be minimized, and hydrogenation activity should be maximized by,for example, increasing the rate constant k_(H) by adding more activecatalyst, or having a higher H₂ partial pressure P_(H2), or increasingthe concentration of catalyst present (w_(H)) relative to the residencetime in free liquid for homogeneous reaction. Eq. 5 teaches that thecarbohydrate concentration can be minimized by limiting the hydrolysisrate k_(OH) and maximizing the hydrogenation rate or the APR rate.

The oxygenated intermediate stream 124 may then pass from the APRreaction to an optional separation stage 126, which produces oxygenatedintermediate stream 128. In some embodiments, optional separation stage126 includes elements that allow for the separation of the oxygenatedintermediates into different components. In some embodiments of thepresent invention, the separation stage 126 can receive the oxygenatedintermediate stream 124 from the APR reaction and separate the variouscomponents into two or more streams. For example, a suitable separatormay include, but is not limited to, a phase separator, stripping column,extractor, or distillation column. In some embodiments, a separator isinstalled prior to the condensation reaction to favor production ofhigher hydrocarbons by separating the higher polyols from the oxygenatedintermediates. In such an embodiment, the higher polyols are recycledback through hydrolysis reactor 114, while the other oxygenatedintermediates are passed to the condensation reaction. In addition, anoutlet stream from the separation stage 118 containing a portion of theoxygenated intermediates may act as in situ generated solvent whenrecycled to the hydrolysis reactor 114. In one embodiment, theseparation stage 126 can also be used to remove some or all of thelignin from the oxygenated intermediate stream. The lignin may be passedout of the separation stage as a separate stream, for example as outputstream 134.

In some embodiments, the oxygenated intermediates are converted to afuel blend that can be used as a fuel additive through hydrogenation ofthe oxygenated intermediates. Various processes are suitable forhydrogenating the oxygenated intermediates. One method includescontacting the feed stream with hydrogen or hydrogen mixed with asuitable gas and a catalyst under conditions sufficient to cause ahydrogenation reaction to form a hydrogenated product. Suitablecatalysts and reaction conditions are described above.

The hydrogenation of the oxygenated intermediates may produce one ormore saturated alcohols, polyols, or hydrocarbons. The alcohols producedin the invention have from 2 to 30 carbon atoms. In some embodiments,the alcohols are cyclic. In another embodiment, the alcohols arebranched. In another embodiment, the alcohols are straight chained.Suitable alcohols for the invention include, but are not limited to,butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol,undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol,hexadecanol, heptyldecanol, octyldecanol, nonyldecanol, eicosanol,uneicosanol, doeicosanol, trieicosanol, tetraeicosanol, and isomersthereof.

The saturated alcohols, polyols, and/or hydrocarbons may be used as afuel blend additive in transportation or other fuels. In addition, theproducts may be sold as commodity chemical for further uses known to oneof ordinary skill in the art.

In some other embodiments, the oxygenated intermediates discussed abovecan be converted into higher hydrocarbons through a condensationreaction shown schematically as condensation reaction 130 in FIG. 1. Inan embodiment, the higher hydrocarbons may be part of a fuel blend foruse as a transportation fuel. In such an embodiment, condensation of theoxygenated intermediates occurs in the presence of a catalyst capable offorming higher hydrocarbons. While not intending to be limited bytheory, it is believed that the production of higher hydrocarbonsproceeds through a stepwise addition reaction including the formation ofcarbon-carbon, or carbon-oxygen bond. The resulting reaction productsinclude any number of compounds containing these moieties, as describedin more detail below.

Referring to FIG. 1, in some embodiments, an outlet stream 128containing at least a portion of the oxygenate intermediates can pass toa condensation reaction. The condensation reaction can comprise avariety of catalysts for condensing one or more oxygenated intermediatesto higher hydrocarbons. The higher hydrocarbons may comprise a fuelproduct. The fuel products produced by the condensation reactorrepresent the product stream from the overall process at higherhydrocarbon stream 110. In an embodiment, the oxygen to carbon ration ofthe higher hydrocarbons produced through the condensation reaction isless than 0.5, alternatively less than 0.4, or preferably less than 0.3.

In the embodiment shown in FIG. 1, the carbohydrates extracted from thebio-based feedstock using a hydrolysis reaction are passed through anAPR reactor to form suitable oxygenated intermediates for thecondensation reaction in condensation reactor 130. In an embodiment, thebio-based feedstock may be

In certain embodiments, suitable condensation catalysts include an acidcatalyst, a base catalyst, or an acid/base catalyst. As used herein, theterm “acid/base catalyst” refers to a catalyst that has both an acid anda base functionality or functional sites. In some embodiments thecondensation catalyst can include, without limitation, zeolites,carbides, nitrides, zirconia, alumina, silica, aluminosilicates,phosphates, titanium oxides, zinc oxides, vanadium oxides, lanthanumoxides, yttrium oxides, scandium oxides, magnesium oxides, ceriumoxides, barium oxides, calcium oxides, hydroxides, heteropolyacids,inorganic acids, acid modified resins, base modified resins, and anycombination thereof. In some embodiments, the condensation catalyst canalso include a modifier. Suitable modifiers include La, Y, Sc, P, B, Bi,Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, and any combination thereof. In someembodiments, the condensation catalyst can also include a metal.Suitable metals include Cu, Ag, Au, Pt, Ni, Fe, Co, Ru, Zn, Cd, Ga, In,Rh, Pd, Ir, Re, Mn, Cr, Mo, W, Sn, Os, alloys, and any combinationthereof.

In certain embodiments, the catalyst described in the condensationreaction can include a catalyst support as described above for thehydrogenation reaction. In certain embodiments, the condensationcatalyst is self-supporting. As used herein, the term “self-supporting”means that the catalyst does not need another material to serve assupport. In another embodiment, the condensation catalyst in used inconjunction with a separate support suitable for suspending thecatalyst. In some embodiments, the condensation catalyst support issilica.

The conditions for which to carry out the condensation reaction willvary based on the type of starting material and the desired products.One of ordinary skill in the art, with the benefit of this disclosure,will recognize the appropriate conditions to use to carry out thereaction. In some embodiments, the condensation reaction is carried outat a temperature at which the thermodynamics for the proposed reactionare favorable. The temperature for the condensation reaction will varydepending on the specific starting polyol or alcohol. In someembodiments, the temperature for the condensation reaction is in a rangefrom 80° C. to 500° C., and preferably from 125° C. to 450° C., and mostpreferably from 125° C. to 250° C. In some embodiments, the condensationreaction is conducted at pressures in a range between 0 Kpa to 9000 KPa,and preferably in a range between 0 KPa and 7000 KPa, and even morepreferably between 0 KPa and 5000 KPa.

In some embodiments, the invention comprises a system having acondensation reactor for reacting the APR product stream in the presenceof a condensation catalyst to produce at least some higher fuel forminghydrocarbons. Each reactor of the invention preferably includes an inletand an outlet adapted to remove the product stream from the reactor. Insome embodiments, the reactors include additional outlets to allow forthe removal of portions of the reactant stream to help maximize thedesired product formation, and allow for collection and recycling ofbyproducts for use in other portions of the system.

The higher hydrocarbons formed by the invention can include a broadrange of compounds depending on the reaction conditions and thecomposition of the oxygenated intermediates fed to the reaction.Exemplary higher hydrocarbons include, but are not limited to, branchedor straight chain alkanes that have from 4 to 30 carbon atoms, branchedor straight chain alkenes that have from 4 to 30 carbon atoms,cycloalkanes that have from 5 to 30 carbon atoms, cycloalkenes that havefrom 5 to 30 carbon atoms, aryls, fused aryls, alcohols, and ketones.Suitable alkanes include, but are not limited to, butane, pentane,pentene, 2-methylbutane, hexane, hexene, 2-methylpentane,3-methylpentane, 2,2,-dimethylbutane, 2,3-dimethylbutane, heptane,heptene, octane, octene, 2,2,4-trimethylpentane, 2,3-dimethyl hexane,2,3,4-trimethylpentane, 2,3-dimethylpentane, nonane, nonene, decane,decene, undecane, undecene, dodecane, dodecene, tridecane, tridecene,tetradecane, tetradecene, pentadecane, pentadecene, nonyldecane,nonyldecene, eicosane, eicosene, uneicosane, uneicosene, doeicosane,doeicosene, trieicosane, trieicosene, tetraeicosane, tetraeicosene, andisomers thereof.

In some embodiments, the cycloalkanes and the cycloalkenes areunsubstituted. In another embodiment, the cycloalkanes and cycloalkenesare mono-substituted. In yet another embodiment, the cycloalkanes andcycloalkenes are multi-substituted. In the embodiments comprising thesubstituted cycloalkanes and cycloalkenes, the substituted groupincludes, without limitation, a branched or straight chain alkyl having1 to 12 carbon atoms, a branched or straight chain alkylene having 1 to12 carbon atoms, a phenyl, and any combination thereof. Suitablecycloalkanes and cycloalkenes include, but are not limited to,cyclopentane, cyclopentene, cyclohexane, cyclohexene,methyl-cyclopentane, methyl-cyclopentene, ethyl-cyclopentane,ethyl-cyclopentene, ethyl-cyclohexane, ethyl-cyclohexene, isomers andany combination thereof.

In some embodiments, the aryls formed are unsubstituted. In anotherembodiment, the aryls formed are mono-substituted. In the embodimentscomprising the substituted aryls, the substituted group includes,without limitation, a branched or straight chain alkyl having 1 to 12carbon atoms, a branched or straight chain alkylene having 1 to 12carbon atoms, a phenyl, and any combination thereof. Suitable aryls forthe invention include, but are not limited to, benzene, toluene, xylene,ethyl benzene, para xylene, meta xylene, and any combination thereof.

The alcohols produced in the invention have from 2 to 30 carbon atoms.In some embodiments, the alcohols are cyclic. In another embodiment, thealcohols are branched. In another embodiment, the alcohols are straightchained. Suitable alcohols for the invention include, but are notlimited to, butanol, pentanol, hexanol, heptanol, octanol, nonanol,decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol,hexadecanol, heptyldecanol, octyldecanol, nonyldecanol, eicosanol,uneicosanol, doeicosanol, trieicosanol, tetraeicosanol, and isomersthereof.

The ketones produced in the invention have from 2 to 30 carbon atoms. Insome embodiments, the ketones are cyclic. In another embodiment, theketones are branched. In another embodiment, the ketones are straightchained. Suitable ketones for the invention include, but are not limitedto, butanone, pentanone, hexanone, heptanone, octanone, nonanone,decanone, undecanone, dodecanone, tridecanone, tetradecanone,pentadecanone, hexadecanone, heptyldecanone, octyldecanone,nonyldecanone, eicosanone, uneicosanone, doeicosanone, trieicosanone,tetraeicosanone, and isomers thereof.

In an embodiment, the condensation reaction may produce a fuel blendcomprising a gasoline fuel. “Gasoline fuel” refer to a hydrocarbon blendpredominantly comprising C₅₋₉ hydrocarbons, for example, C₆₋₈hydrocarbons, and having a boiling point range from 32° C. (90° F.) toabout 204° C. (400° F.). A gasoline fuel includes, but is not limitedto, straight run gasoline, naphtha, fluidized or thermally catalyticallycracked gasoline, VB gasoline, and coker gasoline. The hydrocarboncontent of a gasoline fuel is determined by ASTM Method D2887.

In this embodiment, the condensation reaction may be carried out at atemperature at which the thermodynamics for the proposed reaction arefavorable for the formation of C₅₋₉ hydrocarbons. The temperature forthe condensation reaction will generally be in a range from 275° C. to500° C., and preferably from 300° C. to 450° C., and most preferablyfrom 325° C. to 400° C. The condensation reaction can be conducted atpressures in a range between 0 Kpa to 9000 KPa, and preferably in arange between 0 KPa and 7000 KPa, and even more preferably between 0 KPaand 5000 KPa.

The resulting gasoline fuel blend may be subjected to additionalprocesses to treat the fuel blend to remove certain components orfurther conform the fuel blend to a gasoline fuel standard. Suitabletechniques may include hydrotreating to remove any remaining oxygen,sulfur, or nitrogen in the fuel blend. Hydrogenation may be carriedafter the hydrotreating process to saturate at least some olefinicbonds. Such hydrogenation may be performed to conform the fuel blend toa specific fuel standard (e.g., a gasoline fuel standard). Thehydrogenation step of the fuel blend stream can be carried out accordingto the known procedures, either with a continuous or batch method. Inparticular, it can be effected by feeding hydrogen at a pressure rangingfrom 5 bar to 20 bar and at a temperature ranging from 50° C. to 150° C.and reacting for a time varying from 2 to 20 hours in the presence of ahydrogenation catalyst such as a supported palladium or platinum, forexample 5% by weight of palladium or platinum on activated carbon.

Isomerization may be used to treat the fuel blend to introduced adesired degree of branching or other shape selectivity to at least somecomponents in the fuel blend. It may be useful to remove any impuritiesbefore the hydrocarbons are contacted with the isomerization catalyst.The isomerization step comprises an optional stripping step, wherein thefuel blend from the oligomerization reaction may be purified bystripping with water vapor or a suitable gas such as light hydrocarbon,nitrogen or hydrogen. The optional stripping step is carried out incounter-current manner in a unit upstream of the isomerization catalyst,wherein the gas and liquid are contacted with each other, or before theactual isomerization reactor in a separate stripping unit utilizingcounter-current principle.

After the optional stripping step the fuel blend can be passed to areactive isomerization unit comprising one or several catalyst bed(s).The catalyst beds of the isomerization step may operate either inco-current or counter-current manner. In the isomerization step, thepressure may vary from 20 bar to 150 bar, preferably in the range of 20bar to 100 bar, the temperature being between 200° C. and 500° C.,preferably between 300° C. and 400° C. In the isomerization step, anyisomerization catalysts known in the art may be used. Suitableisomerization catalysts can contain molecular sieve and/or a metal fromGroup VII and/or a carrier. In an embodiment, the isomerization catalystcontains SAPO-11 or SAPO41 or ZSM-22 or ZSM-23 or ferrierite and Pt, Pdor Ni and Al2O3 or SiO2. Typical isomerization catalysts are, forexample, Pt/SAPO-11/Al2O3, Pt/ZSM-22/Al2O3, Pt/ZSM-23/Al2O3 andPt/SAPO-11/SiO2.

Thus, in one embodiment, the fuel blend produced by the processesdescribed herein is a hydrocarbon mixture that meets the requirementsfor a gasoline fuel (i.e., conforms with ASTM D2887).

In an embodiment, the condensation reaction may produce a fuel blendmeeting the requirements for a diesel fuel or jet fuel. Traditionaldiesel fuels are petroleum distillates rich in paraffinic hydrocarbons.They have boiling ranges as broad as 370° F. to 780° F., which aresuitable for combustion in a compression ignition engine, such as adiesel engine vehicle. The American Society of Testing and Materials(ASTM) establishes the grade of diesel according to the boiling range,along with allowable ranges of other fuel properties, such as cetanenumber, cloud point, flash point, viscosity, aniline point, sulfurcontent, water content, ash content, copper strip corrosion, and carbonresidue. Thus, any fuel blend meeting ASTM D975 can be defined as dieselfuel.

The present invention also provides methods to produce jet fuel. Jetfuel is clear to straw colored. The most common fuel is anunleaded/paraffin oil-based fuel classified as Aeroplane A-1, which isproduced to an internationally standardized set of specifications. Jetfuel is a mixture of a large number of different hydrocarbons, possiblyas many as a thousand or more. The range of their sizes (molecularweights or carbon numbers) is restricted by the requirements for theproduct, for example, freezing point or smoke point. Kerosone-typeAirplane fuel (including Jet A and Jet A-1) has a carbon numberdistribution between about C8 and C16. Wide-cut or naphtha-typeAeroplane fuel (including Jet B) typically has a carbon numberdistribution between about C5 and C15. A fuel blend meeting ASTM D1655can be defined as jet fuel.

Both Airplanes (Jet A and Jet B) may contain a number of additives.Useful additives include, but are not limited to, antioxidants,antistatic agents, corrosion inhibitors, and fuel system icing inhibitor(FSII) agents. Antioxidants prevent gumming and usually, are based onalkylated phenols, for example, AO-30, AO-31, or AO-37. Antistaticagents dissipate static electricity and prevent sparking. Stadis 450with dinonylnaphthylsulfonic acid (DINNSA) as the active ingredient, isan example. Corrosion inhibitors, e.g., DCI-4A is used for civilian andmilitary fuels and DCI-6A is used for military fuels. FSII agents,include, e.g., Di-EGME.

A fuel blend meeting the requirements for a diesel fuel (e.g., ASTMD975) or a jet fuel (e.g., ASTM D1655) may be produced using the methodsof the present invention. In an embodiment, a method for producing adiesel fuel blend may comprise: providing a bio-based feedstock;contacting the bio-based feedstock with a catalyst and an solvent toform an intermediate stream comprising carbohydrates; contacting theintermediate stream with an APR catalyst to form a plurality ofoxygenated intermediates, wherein a first portion of the oxygenatedintermediates are recycled to form the solvent; contacting anintermediate oxygenate stream with a condensation catalyst to produce anolefin stream; contacting the olefin stream with an oligomerizationcatalyst to produce higher hydrocarbons, wherein the higher hydrocarbonsmay meet the definition of a diesel fuel or a jet fuel.

In this embodiment, the condensation reaction may be carried out at atemperature at which the thermodynamics for the proposed reaction arefavorable for the formation of olefins with a carbon number ranging fromC₂ to C₈. The temperature for the condensation reaction will generallybe in a range from 80° C. to 275° C., and preferably from 100° C. to250° C., and most preferably from 150° C. to 200° C. The condensationreaction can be conducted at pressures in a range between 0 Kpa to 9000KPa, and preferably in a range between 0 KPa and 7000 KPa, and even morepreferably between 0 KPa and 5000 KPa. The olefin products produced willgenerally comprise one or more unsaturated bonds.

The olefin products produced from the condensation reaction may befurther processed to form a fuel blend meeting the standard for a dieselfuel or a jet fuel. In an embodiment, the olefin products may becontacted with an oligomerization catalyst to produce a fuel blend. Theproducts of an oligomerization reaction of olefins may include primarilyolefins from straight oligomerization or mixtures of olefins, paraffins,cycloalkanes and aromatics. The product spectrum is influenced by bothreaction conditions and the nature of the catalyst. The oligomerizationof olefins over an acidic catalyst (e.g., a zeolite) is influenced bymany factors including thermodynamics, kinetic and diffusionallimitations, and shape-selectivity and side reactions.

Without intending to be limited by theory, it is believed that a numberof reaction mechanisms are responsible for the ultimate productdistribution of the reaction of olefins to form a fuel blend. Forexample, it is believed that the acid-catalyzed oligomerization of theolefins occurs via a carbocationic mechanism resulting in a sequentialchain growth. Molecular weight growth occurs by condensation of any twoolefins to a single higher olefin. Olefins also undergo double bond andskeletal isomerization. In addition to oligomerization, any two olefinsmay react to disproportionate to two olefins of two different carbonnumbers, yielding intermediate or “nonoligomer” olefins. This may tendto randomize the molecular weight distribution of the product withoutsignificantly changing its average carbon number. Olefin cracking mayalso occur simultaneously with oligomerization and disproportionation.Olefins may undergo cyclization and hydrogen transfer reactions leadingto the formation of cycloolefins, alkyl aromatics and paraffins, in whathas been termed conjunct polymerization.

In practice, the kinetics of the oligomerization, disproportionation,and cracking reactions can determine the olefin product distributionunder process conditions. At high temperature or low pressure,thermodynamics drive the reaction products to be distributed in thelight olefin range whereas low temperature and high pressure tends tofavor higher molecular weight olefins. At low temperature, mostly pureoligomers are formed with the majority of the product being trimer andtetramer. With increasing temperature, more disproportionation andcracking and, hence, randomization of the olefin distribution may occur.At moderate temperatures, the product may essentially be random andaverage carbon number can be maximized. In addition to the otherthermodynamic considerations, the reactivity of olefins decreases withincreasing carbon number due to the diffusional limitations within thepore system of the catalyst and the lower probability of coincidentreaction centers of the molecules colliding for a bimolecular reaction.

In some embodiments, the olefinic feed stream may be pretreated toremove any oxygenates or oxygen atoms that may be present in theintermediate olefin stream. The removal of oxygenates from the olefinicstream may take place by various methods known in the art, for example,hydrotreating to remove any excess oxygen, sulfur, or nitrogen.

The oligomerization catalyst with which the olefinic feed stream iscontacted may be an acid catalyst including, but not limited to, azeolite including a shape selective or pentasil ZSM-5 zeolite types. Aspecific zeolite may have a shape selectivity that can be used to form ahigher hydrocarbon that does not contain excessively branchedhydrocarbons. For example, the acid catalyst may comprise a pentacilzeolite with a SiO₂/Al2O3 ratio ranging from about 30 to about 1000 inhydrogen or sodium form. Other zeolites with medium pores (e.g., ZSM-12,-23) may also produce oligomers with a low branching degree due to the“shape selectivity” phenomenon. Other acid catalysts may include, butare not limited to, amorphous acid materials (silico-aluminas), largepore zeolites, resins with cationic exchange, and supported acids (e.g.,phosphoric acid).

In an embodiment, an olefinic oligomerization reaction may be carriedout in any suitable reactor configuration. Suitable configurationsinclude, but are not limited to, batch reactors, semi-batch reactors, orcontinuous reactor designs such as fluidized bed reactors with externalregeneration vessels. Reactor designs may include, but are not limitedto tubular reactors, fixed bed reactors, or any other reactor typesuitable for carrying out the oligomerization reaction. In anembodiment, a continuous oligomerization process for the production ofdiesel and jet fuel boiling range hydrocarbons may be carried out usingan oligomerization reactor for contacting an olefinic feed streamcomprising short chain olefins having a chain length of from 2 to 8carbon atoms with a zeolite catalyst under elevated temperature andpressure so as to convert the short chain olefins to fuel blend in thediesel boiling range. The oligomerization reactor may be operated atrelatively high pressures of about 20 to 100 bar, and at a temperatureof between 150° C. and 300° C., preferably 200° C. to 250° C., with azeolitic oligomerization catalyst.

The reactor design may also comprise a catalyst regenerator forreceiving deactivated or spent catalyst from the oligomerizationreactor. The catalyst regenerator for the regeneration of the catalystmay operate at relatively low pressures of 1 to 5 bar, typically 1 to 2bar and at temperatures of about 500° C. to 1000° C., typically 500° C.to 550° C., to burn off the coke or hydrocarbons fouling the catalyst.Air or oxygen may be introduced to the catalyst regenerator to allow anycoke, carbon, or other deposits on the deactivated catalyst to beoxidized, thus regenerating the catalyst for further use in the reactionprocess.

In an embodiment, the regeneration reactor receives the deactivatedcatalyst from the oligomerization reactor. The deactivated catalyst maybe removed using known means for removing a catalyst from a reactorvessel. In an embodiment, the deactivated catalyst may be removed fromthe oligomerization reactor using a pressure reduction system for takingthe catalyst from the relatively high operating pressure of theoligomerization reactor down to the relatively low operating pressure ofthe catalyst regenerator. The pressure reduction system may include alock hopper and a disengagement hopper, as known to one of ordinaryskill in the art for isolating the high pressure of the reactor from thelow pressure of the catalyst regenerator.

Once the catalyst has been regenerated, the regenerated catalyst may betransferred to the oligomerization reactor using known means fortransporting a catalyst to a reactor vessel. In an embodiment, theregenerated catalyst may be transported to the inlet of theoligomerization reactor using a pressurizing system to increase thepressure of the regenerated catalyst prior introducing the regeneratedcatalyst into the oligomerization reactor. The pressurizing system mayinclude a regenerated catalyst flow control system which is configuredfor safe operation thereof, a lock hopper, and pressure increasingmeans, for example, a venturi compressor, a mechanical compressor, orthe like, to introduce the pressurized regenerated catalyst stream intothe oligomerization reactor.

The resulting oligomerization stream results in a fuel blend that mayhave a wide variety of products including products comprising C₅ to C₂₄hydrocarbons. Additional processing may be used to obtain a fuel blendmeeting a desired standard. An initial separation step may be used togenerate a fuel blend with a narrower range of carbon numbers. In anembodiment, a separation process such as a distillation process is usedto generate a fuel blend comprising C₁₂ to C₂₄ hydrocarbons for furtherprocessing. The remaining hydrocarbons may be used to produce a fuelblend for gasoline, recycled to the oligomerization reactor, or used inadditional processes. For example, a kerosene fraction may be derivedalong with the diesel fraction and can either be used as an illuminatingparaffin, as a jet fuel blending component in conventional crude orsynthetic derived jet fuels, or as reactant (especially C₁₀-C₁₃fraction) in the process to produce LAB (Linear Alkyl Benzene). Thenaphtha fraction after hydroprocessing can be routed to a thermalcracker for the production of ethylene and propylene or routed to as isto a catalytic cracker to produce ethylene, propylene, and gasoline.

Additional processes may be used to treat the fuel blend to removecertain components or further conform the fuel blend to a diesel or jetfuel standard. Suitable techniques may include hydrotreating to removeany remaining oxygen, sulfur, or nitrogen in the fuel blend.Hydrogenation may be carried after the hydrotreating process to saturateat least some olefinic bonds. Such hydrogenation may be performed toconform the fuel blend to a specific fuel standard (e.g., a diesel fuelstandard or a jet fuel standard). The hydrogenation step of the fuelblend stream can be carried out according to the known procedures,either with the continuous or batch method. In particular, it can beeffected by feeding hydrogen at a pressure ranging from 5 bar to 20 barand at a temperature ranging from 50° C. to 150° C. and reacting for atime varying from 2 to 20 hours in the presence of a hydrogenationcatalyst such as a supported palladium or platinum, for example 5% byweight of palladium or platinum on activated carbon.

Isomerization may be used to treat the fuel blend to introduced adesired degree of branching or other shape selectivity to at least somecomponents in the fuel blend. It may be useful to remove any impuritiesbefore the hydrocarbons are contacted with the isomerization catalyst.The isomerization step comprises an optional stripping step, wherein thefuel blend from the oligomerization reaction may be purified bystripping with water vapor or a suitable gas such as light hydrocarbon,nitrogen or hydrogen. The optional stripping step is carried out incounter-current manner in a unit upstream of the isomerization catalyst,wherein the gas and liquid are contacted with each other, or before theactual isomerization reactor in a separate stripping unit utilizingcounter-current principle.

After the optional stripping step the fuel blend can be passed to areactive isomerization unit comprising one or several catalyst bed(s).The catalyst beds of the isomerization step may operate either inco-current or counter-current manner. In the isomerization step, thepressure may vary from 20 bar to 150 bar, preferably in the range of 20bar to 100 bar, the temperature being between 200° C. and 500° C.,preferably between 300° C. and 400° C. In the isomerization step, anyisomerization catalysts known in the art may be used. Suitableisomerization catalysts can contain molecular sieve and/or a metal fromGroup VII and/or a carrier. In an embodiment, the isomerization catalystcontains SAPO-11 or SAPO41 or ZSM-22 or ZSM-23 or ferrierite and Pt, Pdor Ni and Al2O3 or SiO2. Typical isomerization catalysts are, forexample, Pt/SAPO-11/Al₂O₃, Pt/ZSM-22/Al₂O₃, Pt/ZSM-23/Al₂O₃ andPt/SAPO-11/SiO₂.

Thus, in one embodiment, the fuel blend produced by the processesdescribed herein is a hydrocarbon mixture that meets the requirementsfor jet fuel (i.e., conforms with ASTM D1655). In another embodiment,the product of the processes described herein is a hydrocarbon mixturethat comprises a fuel blend meeting the requirements for a diesel fuel(i.e., conforms with ASTM D975).

The methods and systems for producing higher hydrocarbons and/or a fuelblend from bio-based feedstocks can have an increased relative fuelyield as compared to other bio-based feedstock conversion processes. Asused herein, the term “relative fuel yield” takes into account thepercentage of carbon atoms that are extracted as carbohydrates,exclusive of lignins, from a bio-based feedstock that are present in thehigher hydrocarbons produced as a product on a mole basis. The relativefuel yield is relative to yield obtained from feeding an amount ofsorbitol equivalent to the total amount of carbohydrates extracted fromthe bio-based feedstock on a carbon basis into the processing reaction.The relative fuel yield can be calculated by dividing the total amountof carbon present in the higher hydrocarbons formed from the process bythe total amount of carbon present in the higher hydrocarbons obtainedfrom feeding sorbitol into the processing reaction. The total mass ofcarbon in the higher hydrocarbons can be directly measured at the outletof the fuel processing reaction (e.g., the hydrogenation reaction, thecondensation reaction, the oligomerization reaction) or at any point atwhich the higher hydrocarbons are ready to exit the process.

In an embodiment of the present invention, the relative fuel yield ofthe current process may be greater than other bio-based feedstockconversion processes. Without wishing to be limited by theory, it isbelieved that the use of a multi-temperature hydrolysis reaction processalong with the direct APR of the extracted compounds allows for agreater percentage of the bio-based feedstock to be converted intohigher hydrocarbons while limiting the formation of degradationproducts. In an embodiment, the relative fuel yield of the process canbe greater than or equal to 60%, or alternatively, greater than or equalto 70%.

To facilitate a better understanding of the present invention, thefollowing examples of certain aspects of some embodiments are given. Inno way should the following examples be read to limit, or define, theentire scope of the invention.

EXAMPLES Aqueous Phase Reforming Experiments

Direct aqueous phase reforming (APR) experiments were conducted in100-ml stirred reactors with draft-tube gas-induction impeller (ParrSeries 4590). Reaction tests for direct bio-based feedstock reformingentailed filling the reactor with 60-grams of solvent (deionized water,or a mixture of DI water and isopropanol (IPA), and 3-3.5 grams ofbio-based feedstock comprising biomass (bagasse, or pine sawdust)). One(1) gram of acetic acid was optionally charged to facilitate biomasshydrolysis.

Bagasse was milled via a 1-mm grate. Dry, debarked Loblolly pine wasground via blender (Thomas Scientific) and sieved to less than 30 mesh.Dry solids fraction was determined by vacuum drying at 80° C.-82° C. Onegram of aqueous phase reforming catalyst (reduced 5% Pt/C catalyst at50% moisture, or powdered 1.9% Pt/Al₂O₃) was charged to the reactor,which was charged with 600 psi of hydrogen or nitrogen. To minimizedegradation of hydrolysate to heavy ends, each reactor was typicallyheated with a staged temperature sequence of one hour at 160° C., 190°C., 225° C., and finally 250° C., before leaving overnight at the finalsetpoint.

Comparison tests were also conducted with glucose or sorbitol feddirectly to the reaction in place of biomass, to simulate and quantifyconversion of model hydrolysate to APR intermediates. Glucose is one ofthe sugars readily leached from biomass in hot water, while sorbitol isreadily formed via hydrogenation of glucose, where platinum or othercatalysts capable of hydrogenation are present.

A batch reaction time of 20 hours under these conditions corresponds toa weight hourly space velocity (g-feed/g-catalyst/h) of about 3, for acomparable continuous flow reactor. A 0.5-micron sintered metal filterattached to a dip tube allowed liquid samples to be taken throughout thecourse of reaction, without loss of biomass or catalyst.

Samples were analyzed by an HPLC method based on combined size and ionexclusion chromatography, to determine unreacted sorbitol, and amount ofC₃ and smaller polyols formed: glycerol (Gly), ethylene glycol (EG), and1,2-propylene glycol (PG). Additional GC analysis via a moderatepolarity DB-5 column were conducted to assess formation of C₆ andlighter oxygenates (ketones, aldehydes, alcohols). A separate GCequipped with thermal conductivity and flame ionization (FID) detectorsfor refinery gas analysis, were used for detection of H₂, CO₂, and lightalkanes C₁-C₅. GC-mass spec was used to characterize select APR reactionproduct mixtures. Table 1 lists compounds identified in the aqueousphase following aqueous phase reforming of sorbitol.

While oxygenates formed during APR can be blended to fuel, condensationover a strong acid catalyst yields a direct blend suitable for gasoline.ZSM-5 zeolite provides an aromatic-rich blend. Effectiveness of theinitial APR step can be assessed via passing the APR reaction productover ZSM-5, to characterize the yield of gasoline-range components.These tests were conducted via a pulse microreactor formed via packing aGC injector 0.05 grams of ZSM-5 acid condensation catalyst, and held at375° C. One-microliter of APR reactor product was injected into thecatalyst bed, to examine formation of liquid fuel products. Thecatalytic injector insert was followed by Restek Rtx-1701 and DB-5capillary GC columns in series, to resolve hydrocarbon and aromaticreaction components via temperature-programmed analysis.

A mass-sensitive flame ionization detector (FID) was used for analysisto characterize the yields, such that GC areas for alkane and aromatichydrocarbon products from the condensation step, can be related to theamount of carbon charged as “feed” for the aqueous phase reforming step.A comparison run (Example 3) was conducted with 25 wt % sorbitol as thefeed to APR, where sorbitol represents the fully hydrolyzed andhydrogenated C₆ sugar which can be extracted from biomass. Total mass ofliquid alkane and aromatic products formed via acid condensationfollowing APR reaction with sorbitol as feed, as indicated by the totalarea of the FID response, relative to the wt % C charged as sorbitolfeed, was assigned a yield value of fuel/bio-carbon of 1.0. Fuel yieldsper wt % C charged as feed, were similarly computed from the FIDresponse of the condensation pulse microreactor, for runs using biomassas feed.

Examples 1-3 Direct Aqueous Phase Reforming of Bagasse

Batch APR reactions with bagasse as feed, and with a comparison of 25%sorbitol as feed, were performed as described above. 1.7% acetic acidwas added to simulate catalysis of hydrolysis by recycle acid. Productsformed from this concentration of acetic acid were subtracted from totalproduct formation, to calculate the net production of liquid fuels frombagasse.

For Example 1, the yield of liquid fuels products (per unit wt % C) wasobserved to increase, as temperature was increased stage wise via thesequence 160, 190, and 225° C. A further increase in temperature withheating overnight let to a slight decrease in yield per carbon fed.Overall yields from bagasse were calculate as 82% of the yield/Cobtained with model compound sorbitol as feed (Example 3). This comparesfavourably with the 77% hydrolysable fraction of dry bagasse, whichcontains 20% lignin and 3% ash. Results thus indicate that all sugarprecursors present in bagasse were hydrolyzed, and selectively convertedto liquid biofuel.

Example 2 examined yields for a similar experiment where hot water plusacetic acid hydrolysis was conducted first, without the concertedpresence of Pt/C APR catalyst. While a small yield/C was obtainedfollowing thermal contacting at 225° C. in Example 2A, the yieldobtained from acid condensation diminished upon further heating to 250°C., in the absence of catalyst (Example 2B). Pt/C catalyst was thenadded to the resulting liquid for Example 2C, to effect aqueous phasereforming of hydrolysate from the initial heating step. Yields/C wereless than those obtained from the 1.7% acetic acid added as hydrolysiscatalyst, when the resulting liquid was pulsed over ZSM-5 condensationcatalyst.

This result shows the critical importance of concerted APR reaction withhydrolysis of biomass. In the absence of concerted aqueous phasereforming, the hydrolysate undergoes irreversible degradation(presumably to heavy ends), and cannot be reverted to liquid fuels uponsubsequent APR and condensation.

TABLE 1 Direct APR of Biomass % CHO Tmax Liquid fuel Ex # Feed activesCatalyst ° C. Total hours Yield/C 1A Bagass 5.50% 5% Pt/C 160 1.0 0.0681B Bagass 5.50% 5% Pt/C 190 2.0 0.601 1C Bagass 5.50% 5% Pt/C 225 3.00.821 1D Bagass 5.50% 5% Pt/C 250 21.0 0.739 2A Bagass 5.50% none 2252.5 0.210 2B Bagass 5.50% none 250 21.0 0.070 2C Cycle 2B 5.50% 5% Pt/C250 3.0 −0.041 3A Sorbitol   25% 5% Pt/C 250 22.3 1.000

Table 2 shows the selectivity to alkanes and aromatics followingcondensation over ZSM-5, for the examples of Table 1. The mixture isconsidered suitable for blending as gasoline.

TABLE 2 Condensation Product Compositions Al- Ben- Et 3 Me- kanes zeneToluene Benz Xylenes benz Napth's Total Ex# wt % wt % wt % wt % wt % wt% wt % wt % 1A 67.7 8.30 8.15 −2.04 −0.42 −6.84 25.62 100.5 1B 44.3 7.8919.07 5.66 8.30 1.29 11.02 97.6 1C 45.7 7.55 19.25 9.96 4.58 1.52 9.7298.3 1D 63.2 6.01 10.56 4.95 2.93 1.72 7.60 97.0 2A 61.6 7.86 11.0012.06 5.21 −1.26 21.96 118.4 2B 41.7 7.98 12.61 3.68 0.90 −2.53 45.34109.7 2C na na na na na na na 0.0 3A 28.0 10.3 17.8 1.2 15.3 7.2 14.894.5 3 Me-benz = trimethylbenzenes; Et Benz = ethyl benzenes; napth's =napth's = naphthalenes

Characterization of the intermediates formed from the APR step ofExample 3A is given in Table 3. APR of sugar or sugar alcohol results ina plethora of mono-, di, and tri-oxygenate compounds, includingcarboxylic acids which cause a drop in pH to ca. 3.5-4.0. These acidscan catalyze hydrolysis of biomass, upon recycle of the reactionmixture.

TABLE 3 Components identified in Aqueous Phase Reforming (APR) ofsorbitol [GC-MS]. Propionaldehyde Acetone 2,5-DimethyltetrahydrofuranTetrahydrofuran + Vinyl formate 2-Methyltetrahydrofuran MethanolIsopropyl acetate + 2-Butanone Tetrahydropyran Isopropyl Alcohol Ethanol2-Pentanone & 3-Pentanone 2-Butanol n-Propanol 3-Hexanone 2-Hexanone2-Methylcyclopentanone 3-Hexanol 3-Methylcyclopentanone 2-Hexanol1-Pentanol Dihydro-2-methyl-3(2H)-Furanone 3-Hydroxy-2-butanone2-Methyl-1-pentanol Ethyl lactate 1-Hexanol 1-Hydroxy-2-butanone Aceticacid 2,5-Hexanedione Propionic acid 2,3-Butanediol + Isobutyric AcidPropylene glycol Ethylene glycol Butyric acid Valeric acid Hexanoic acidGlycerol Isosorbide 2,5-Dimethyltetrahydrofuran 2,3-Butanediol +Isobutyric Acid

Examples 4-12

Table 4 shows direct biomass APR and hydrogenation experiments withbagasse as feedstock. Acetic acid and isopropanol (IPA) were added tosimulate intermediates from bioforming which are known to assist inbiomass hydrolysis and solubilization. At the end of these experiments,the reaction mixture was filtered on Whatman #2 filter paper to recovercatalyst and undigested bagasse, from which a percent “digested” couldbe calculated. As used herein, “digested” means soluble enough to passthrough a Whatman #2 filter paper after cooling to room temperature.

The minimum “digested” bagasse was 70.9%, and in many cases the digestedbagasse approached 100%. Filtered samples were not analyzed for ashcontent for current experiments. The extent to which acetic acidaddition may have solubilized salts as acetate is unknown. Certainly,digestion greater than 70% indicates solubilization of lignin, which wasexpected where IPA was added as initial solvent. Light alcohols capableof solubilizing lignins were also be generated during APR of sugars orsugar alcohols.

TABLE 4 Direct Biomass APR or hydrogenation Bagass Acetic IPA Wt % GasTmax Time Percent Ex # wt % acid wt % wt % Catalyst catalyst phase ° C.hours digest  4 4.8% 0.0% 0.0% 5% Pt/C 0.72% H2 160 125.0 70.9%  5 4.8%2.0% 50.0% 5% Pt/C 0.72% H2 250 23.0 97.2%  6 4.8% 2.0% 50.0% 5% Pt/C0.71% H2 250 12.0 104.6%  7 4.8% 2.0% 50.0% 5% Ru/C 0.71% H2 250 8.7102.5%  8 4.8% 2.0% 0.0% 5% Ru/C 0.77% H2 250 20.0 102.6%  9 4.8% 2.0%50.0% None 0.00% H2 250 5.0 88.5% 10 5.5% 1.0% 0.0% 5% Pt/C 0.83% H2 25023.0 98.9% 11 5.5% 1.2% 0.0% None 0.00% N2 250 20.0 N/A 11B 5.5% 1.2%0.0% +Pt/C & H2 0.82% H2 260 4.0 84.5% 12 4.7% 1.1% 50.0% None 0.00% N2250 8.0 95.3%

Both ruthenium hydrogenation catalyst and platinum APR catalysts wereused. For ruthenium, the expected pathway is one of hydrogenation ofhydrolyzed biomass to form sugar alcohols at temperatures below 200° C.,and further hydrogenolysis to form polyols such as ethylene glycol (EGor MEG for “mono”), propylene glycol (PG or MPG), glycerol, or evenisosorbide via dehydration. For APR, the reaction products were reformedby platinum to give smaller molecular weight species amenable tocondensation to liquid hydrocarbon fuels. Where IPA was added at 50%,solutions remained crystal clear with a yellow color for weeks ofstorage. Where IPA was not added, solutions would flock and precipitateover a period of time (days). The black precipitate formed at the bottomof sample vials since it was denser than water. All solutions that weresampled via dip tube with 5-micron filter. Addition of IPA, acetic acid,and catalyst generally increased the extent of digestion per unit time.Very high digestion was accomplished via use of catalyst together withacetic acid, or with IPA/acetic combination without catalyst.

Therefore, the invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularillustrative embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. While compositions and methods are described in terms of“comprising,” “containing,” or “including” various components or steps,the compositions and methods can also “consist essentially of” or“consist of” the various components and steps. All numbers and rangesdisclosed above may vary by some amount. Whenever a numerical range witha lower limit and an upper limit is disclosed, any number and anyincluded range falling within the range is specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues. Also, the terms in the claims have their plain, ordinary meaningunless otherwise explicitly and clearly defined by the patentee.Moreover, the indefinite articles “a” or “an”, as used in the claims,are defined herein to mean one or more than one of the element that itintroduces. If there is any conflict in the usages of a word or term inthis specification and one or more patent or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

Example 13

The 100-ml batch reactor was charged with 28.28 grams of isopropanol(IPA), 28.41 grams of deionized water, 1.018 grams of acetic acid, 0.995grams of 5% Pt/C APR catalyst, and 3.478 grams of 1 micron milledbagasse at 4.7% moisture. The reactor was heated with mixing to 175° C.,200° C., 225° C., and finally 250° C. for 1.5-hour increments, beforeleaving overnight (23 hours total). Liquid and gas phase samples weretaken, before cooling to add an additional amount of pine sawdust (3.51,3.20, 2.99, and 2.95 grams) for 4 additional cycles. Cumulative additionafter five cycles corresponded to 21.1 wt % dry solids addition to thefinal reactor mixture. By staging addition of biomass solids, a moderateviscosity slurry with free liquid was maintained.

Recovery of undigested solids by filtration indicated 94% of the bagassedry solids had been converted to liquid products and/or solubilised inthe reaction mixture. A GC analysis of the both oil and aqueous phasesindicated an estimated 11% wt % liquid product formation relative to amaximum expected value of 9.1% basis carbon content of feed charged.Observed liquid products were more volatile than sorbitol, basis GCretention times. The experiment demonstrates an ability to solubiliseand reform biomass via direct APR, to obtain concentrations ofintermediates in excess of 5 wt %, as required for economic processingin subsequent condensation reactions.

Example 14

The 100-ml batch reactor was charged with 30.182-g of isopropanol (IPA)and 30.069 grams of deionized water. 1.0515 grams of acetic acid wereadded as simulated recycle hydrolysis catalyst. 1.0505 grams of 5% Pt/CAPR catalyst (50% wet) were also charged. 3.53 grams of Loblolly pine(<30 mesh, 18% moisture) were charged for an initial cycle, along with87 kPa of H₂. The reactor was heated with mixing to 175° C., 200° C.,225° C., and finally 250° C. for 1.5-hour increments, before leavingovernight (23 hours total). Liquid and gas phase samples were taken,before cooling to add an additional amount of pine sawdust (3.47, 3.48,3.50, and 3.51 grams) for 4 additional cycles. Cumulative addition afterfive cycles corresponded to 22.9 wt % dry solids addition to the finalreactor mixture. By staging addition of biomass solids, a moderateviscosity slurry with free liquid was maintained.

Recovery of undigested solids by filtration indicated 78% of the pinedry solids had been converted to liquid products. A GC analysis of theliquid phase verified 5.9 wt % of liquid products formed with retentiontimes less than sorbitol, relative to a maximum 7.6 wt % possible fromcarbon present in feed, at this conversion. These results show anability to hydrolyze and reform softwood (pine) to liquid fuels(oxygenates), to obtain a concentration of greater than 5 weightpercent, as desired for separation and use as a fuel additive, or foreconomic further processing via condensation to liquid fuels.

1.-23. (canceled)
 24. A method comprising: providing a biomass solid;contacting the biomass solid with a solvent and APR catalyst in thepresence of hydrogen in a reactor to form a plurality of oxygenatedintermediates thereby providing an oxygenated intermediate stream,wherein a first portion of the oxygenated intermediates are recycled toform the solvent; and processing at least a second portion of theoxygenated intermediates to form a fuel blend.
 25. The method of claim24 wherein the biomass is wood materials.
 26. The method of claim 24wherein the biomass is agricultural wastes.
 27. The method of claim 24wherein the biomass is energy crops.
 28. The method of claim 24 whereinthe contacting is carried out at a temperature in the range of 80° C. to300° C.
 29. The method of claim 28 wherein the contacting is carried outat a pressure in the range of 60 KPa to 16500 KPa.
 30. The method ofclaim 24 wherein the lignin is removed from the oxygenated intermediatestream.
 31. The method of claim 28 wherein the processing of at least asecond portion of the oxygenated intermediates comprises contacting atleast the second portion of the oxygenated intermediates with ahydrogenation catalyst to form the fuel blend.
 32. The method of claim28 wherein the processing of at least a second portion of the oxygenatedintermediates comprises contacting at least the second portion of theoxygenated intermediates with a condensation catalyst to form the fuelblend.
 33. The method of claim 28 wherein the processing of at least asecond portion of the oxygenated intermediates comprises contacting atleast the second portion of the oxygenated intermediates with an acidcatalyst to form at least some olefins; and contacting the olefins withan oligomerization catalyst to form the fuel blend.
 34. A direct aqueousphase reforming system of biomass comprising: an APR reactor containingan APR catalyst comprising an inlet for receiving the biomass, an inletfor receiving solvent, and an inlet for receiving hydrogen, and anoutlet for discharging an oxygenated intermediate stream, a separatorcomprising an inlet for the oxygenated intermediate stream, wherein afirst portion of the oxygenated intermediate stream is recycled to theAPR reactor as the solvent and a second portion of the oxygenatedintermediate stream is provided to a fuel processor reactor; and a fuelsprocessing reactor comprising an inlet for receiving the second portionof the oxygenated intermediate stream and an outlet for discharging afuel blend.
 35. The system of claim 34 wherein the separator furthercomprises an outlet for lignin.